The High Court in Glasgow heard that 44-year-old Allan McLeod, who carried out his abuse for almost 10 years, posed a high risk to the public.
Yesterday, judge Michael O'Grady, QC, imposed a lifelong restriction order on McLeod and sentenced him to at least four years in prison.
Judge O'Grady described McLeod's offending as "an appalling course of criminal conduct. He added: "For little short of a decade, for your own gratification, you horribly abused these children with regularity and cynicism."
McLeod carried out abuse every Saturday while he was babysitting in a house in East Kilbride, South Lanarkshire.
Throughout his trial, he insisted he was innocent and claimed the children had made the incidents up.